Physics Builder Tools > Features > Auxiliary Settings (Feature Nodes)

Auxiliary Settings (Feature Nodes)
A feature can have one Auxiliary Settings node () that contains a collection of various settings for its parent feature that you usually do not need to change.
Auxiliary Settings nodes can be added to the parent Features nodes under the Building Blocks branch, or to the features added under a Physics Interface or Multiphysics Interface. Right-click the Auxiliary Settings node to add Geometric Nonlinearity, Physics Symbol, and Usage Condition subnodes.
The Settings window has the following sections:
GUI Attributes
Enter a valid image file name in the Icon field to use a different icon for the feature. If this field is empty, the feature uses a default icon, which is different depending on the feature’s entity level.
Harmonic Perturbation
Select the Perturbation method from the list that has the following options:
No perturbation support (the default).
Can act as contribution. Enables an option so that a user can choose if a feature instance can act either as a stationary contribution or as a harmonic contribution. This option only makes sense for contributing features.
Can add contribution as child. Adds a subfeature to this feature that adds the harmonic contribution. This is typically used for exclusive features. From the Harmonic contribution feature list, choose Automatic generation of the subfeature or link to a feature with the From link option. The automatically generated subfeature adds harmonic contributions for all variables in the parent feature that are defined under a user input and that have the preference property Interpret as right-hand-side selected.
Visibility of Model Inputs
This setting requires that the Include model input check box in the Feature node's Preference section is selected. A model input is by default only shown when a material requests it. In the Always visible list, add the model inputs that ignore the materials so that they should always appear in the Settings window of the feature instance.
Load- and Constraint Grouping
This section has the settings Enable load groups and Enable constraint groups which can be selected to make the physics feature compatible with the Load cases functionality of COMSOL Multiphysics. When load- or constraint groups are enabled for a feature it gets extra menu-items so that the user can select under which group it is active. To make the physics feature useful under load grouping the variables that should be affected by the grouping need to have the Include in load groups setting selected in the Variable declaration node. Constraints are by default affected by the constraint grouping. If a particular constraint should not be affected by the grouping, then select the Exclude from constraint grouping setting in the Constraint node.
Feature Selection
This section contains settings that affect the entities on which the physics feature is applicable. The setting in the Take selection from list controls the maximum selection from which the feature can take its selection. That is the selection that is further restricted by the Applicable entities setting of the physics feature. The default option, Parent, means that the selection should be taken from the physics or in the case of a subfeature from the parent feature. Physics means that the selection should be taken from the physics even in the case of a subfeature. The last option, Geometry, indicates that the feature should take its selection from the entire geometry.
The other settings are the Not applicable on infinite element domain and Not applicable on perfectly matched layer domain check box. Select any of these check boxes to make sure that the physics feature cannot be applied on a domain of the particular type.
Input coordinate system
When any of the base vector systems choices of the parent physics feature are Selected input coordinate system, this section has settings that control the input coordinate system. First, there is a Coordinate section list with the options Add coordinate system section (the default) and Use parent’s coordinate systems section. The latter choice disables all other settings and uses the Coordinate System Selection section from the parent if there is any. The Add coordinate system section option adds a Coordinate System Selection section to the physics feature. It also enables a couple of other settings that control this section. Select the Only allow orthonormal systems check box to only allow the user to choose between orthonormal systems when selecting the input coordinate system of the feature. In the Filtering of systems list, choose between the options Allow boundary systems, No boundary systems, and Only boundary systems. Note that the filtering only affects features that live on the boundary geometric entity level.